This invention is in the field of retractors typically used with seat and shoulder belt systems.
Many patents have issued that disclose an automatic retractor device that provides a spring-biased spool for urging a webbed belt around the spool and thus into the retractor, but also providing mechanisms rendering the spring-biased spool yieldable to permit the webbed belt to be withdrawn from the retractor spool so that the opposite end of the webbed belt may be attached to a buckle or tongue. Typically, the prior art retractors are operable to permit more than the desired amount of webbed belt material to be withdrawn from the retractor spool while the operator is attaching the opposite end of the belt to a tongue or buckle. The spring-biased spool will then rewind the excess belt withdrawn back into the retractor, thereby applying a snug tension to the webbed belt.
Various mechanisms are known in the prior art for locking the spool, and thus the retractor, after snug tension around the operator has been achieved to prevent withdrawal of the webbed belt from the retractor in emergency conditions. The mechanisms found in what are known in the art as emergency locking retractors provide dual sensitive locking means. Such retractors are sensitive to (1) webbed belt acceleration, locking the spool when the webbed belt's acceleration off the spool and out of the retractor exceeds a predetermined maximum; and to (2) vehicle acceleration, locking the spool when changes in the vehicle's acceleration jar an acceleration-sensitive pendulum device within the retractor into spool-locking engagement. Such an acceleration-sensitive pendulum device for use within an emergency locking retractor is disclosed in U.S. Pat. No. 4,382,564, issued to James, and is incorporated herein by reference.
Emergency locking retractors are typically utilized in three-point seat and shoulder belt restraining systems. Referring to Prior Art FIG. 7, in a typical three point system, an emergency locking retractor 74 is permanently affixed to the vehicle, typically below shoulder level of the operator, and is oriented so the webbed belt 16 within the retractor exits the retractor vertically and upward. From the retractor 74, the webbed belt 16 is led through the first point of the three-point system, which is typically a first D-ring assembly 76 affixed to the vehicle directly above retractor 74 and above shoulder level of the operator. First D-ring assembly 76 permits the webbed belt 16 to slidably pass through the assembly and be turned downward over the shoulder and diagonally across the chest of the operator. The webbed belt 16 then is led directly to the second point of the three-point system, which is typically a second D-ring assembly 78 that is attached to a tongue 80. Tongue 80 is then insertable into a buckle 82 that is permanently affixed to the vehicle, typically below waist level of the operator. Second D-ring assembly 78 also permits the webbed belt 16 to slidably pass through the assembly and be turned across the lap of the operator whereafter the webbed belt 16 is deadened by permanent attachment to the vehicle, also at a point typically below waist level of the operator, thereby becoming the third point of the three-point system 84. When the operator inserts tongue 80 into buckle 82 the three-point seat and shoulder belt retraction system is closed and operational.
It is known to provide an emergency locking retractor in a three-point system, as described above, as an operator restraining device in moving vehicles of all types. A typical application is in the passenger automobile, both foreign and domestic. With appropriately-adjusted webbed belt accleration sensitivity and vehicle acceleration sensitivity, the operator has adequate freedom of movement even while otherwise restrained in the closed three-point system. The webbed belt can be withdrawn from the retractor at rates of acceleration less than that which would lock the retractor, and the passenger car being fairly smooth riding, changes in vehicle acceleration in normal operation would not be expected to jostle the acceleration-sensitive pendulum device within the retractor into spool-locking engagement.
In applications of the emergency locking retractor within a three-point system wherein the operator and the vehicle are jolted and bounced in dramatic contrast to the ride experienced in the normal passenger car, such as in semitrailer cabs, the snug tension upon the webbed belt experienced at rest can be repeatedly eased as the operator is bounced in the seat. In semitrailer cabs, for example, the operator's seat is typically a suspension seat dampened by air cylinders. It is typical for the operator's suspension seat to move fore and aft by three (3) to four (4) inches and to move up and down to the same degree during normal operations. With each downward or rearward bounce, the snug tension on the webbed belt can be loosened to such a degree that the spring-biased spool of the emergency locking retractor operates to retract webbed belt onto the retractor spool until a snug tension is reestablished. If the upward or forward rebound does not accelerate the webbed belt at the rate necessary to lock the retractor, and if the vehicle's jostling does not otherwise cause the pendulum device within the retractor to move into spool-locking engagement, the operator will experience only the continual discomfort of the webbed belt chafing the operator's shoulder and upper body as the operator's upward and forward rebounds cause the webbed belt to be withdrawn from the spool.
On the other hand, if the upward or forward rebounds of the operator accelerate the webbed belt at a rate that will cause the retractor spool to lock, or if the vehicle's jostling is sufficient to cause the acceleration sensitive pendulum device within the retractor to move into spool-locking engagement, the operator will experience the greater discomfort of the webbed belt suddenly locking upon the operator's rebound, restraining the operator in the downward or aft position. As the rate of acceleration of the webbed belt decreased, the webbed belt acceleration-sensitive locking mechanism of the retractor would unlock, thereby allowing the webbed belt to be withdrawn from the retractor spool. However, the vehicle acceleration-sensitive locking mechanism of the emergency locking retractor typically requires the webbed belt to be retracted slightly onto the retractor spool before it will be released from its spool-locking engagement. Therefore, the operator could be restrained in the downward or aft bounce position by reason of the vehicle acceleration-sensitive locking mechanism of the retractor even thought the webbed belt acceleration and the vehicle inertia had decreased.
Disclosed herein is a novel belt retraction locking device for use in a three-point seat and shoulder belt retraction system utilizing an emergency locking retractor. The disclosed device allows the operator to manually counterbalance the spring bias of the emergency locking retractor spool to thereby deactivate the retractor spool's normal urging of the webbed belt into a retracted condition after the operator has comfortably tensioned the webbed belt. The subsequent movements of the operator that result in easing of the snug tension upon the webbed belt will therefore not result in the webbed belt being withdrawn into the retractor. The disclosed belt retraction locking device is also operable to automatically unlock the webbed belt, thereby releasing the webbed belt from the influence of the disclosed device, when the operator forcibly tensions the webbed belt, such as would occur when the operator of a semitrailer cab leans far forward and over the steering wheel, as he sometimes must, to facilitate turning the vehicle sharply. Absent such automatic unlocking, the operator would be restrained from forward movement beyond that which had been accommodated by the original tensioning of the webbed belt, for the belt retraction locking device would not only prevent retraction of the webbed belt into the retractor but also additional withdrawal of the webbed belt as well.